The objective of this Core is to provide expert advice from the talented team of co-investigators, necessary training, and the infrastructure to utilize molecular biological approaches to create genetically engineered mouse models that will increase the depth and breadth of existing drug abuse research and stimulate new research at Virginia Commonwealth University and throughout the scientific community. Additionally, it will provide a mechanism for scientists both within and outside of the drug abuse field to interact to develop new research projects. Specifically, this Core will provide investigators the necessary training, tools, and expertise to: 1) create novel genetically modified mice, not currently available through other sources; 2) maintain mice in a repository in which available mouse lines will be bred, genotyped, and transferred to the investigator upon weaning; 3) cryogenically preserve mouse lines for use in future studies; 4) develop viral vectors to over-express, knock-down or deliver dominant negative forms of study genes chosen by collaborating investigators; and 5) deliver viral vectors stereotaxically into specific brain regions of interest and verify the extent of the manipulation. Overall this Core will provide new services to multiple investigators, with the goals of providing state-of-the-art molecular biological tools to investigate drugs of abuse, facilitate collaborations, and provide value to drug abuse researchers.